Telenomus remus Nixon egg parasitization of three species of Spodoptera under different temperatures.

Telenomus remus Nixon is a promising biocontrol agent as an egg parasitoid of Spodoptera spp., but the lack of information on the host-parasitoid interactions in this system precludes its applied use in agriculture. Therefore, we studied the parasitism capacity of T. remus on eggs of Spodoptera cosmioides (Walker), Spodoptera eridania (Cramer), and Spodoptera frugiperda (Smith) in a range of temperatures (19, 22, 25, 28, 31, and 34 ± 1°C) under controlled conditions (70 ± 10% RH and 12 h photophase). Egg masses of Spodoptera spp. were offered to a single-mated T. remus female on a daily basis. More than 80% lifetime parasitism on eggs of S. cosmioides, S. frugiperda, and S. eridania was reached from 1 to 5, 1 to 7, and 1 to 9 days, respectively, at temperatures from 19 to 34°C. More than 80% parasitization was obtained at extreme temperatures for all hosts studied. Lifetime parasitization of S. frugiperda, S. cosmioides, and S. eridania was affected by temperature, with the lowest values for S. frugiperda (34°C) and S. cosmioides (19 and 34°C). Parasitization of S. eridania eggs was reduced around 18% at 28 and 31°C, but dropped more severely at 34°C. Parasitoid longevity was reduced as temperature increased. Thus, our data indicated that T. remus might be suitable as a biocontrol agent against S. eridania, S. cosmioides, and S. frugiperda in geographical areas that fit the temperature range studied here, even though T. remus parasitism was reduced at 34°C.

Resistance of soybean genotypes to Bemisia tabaci (Genn.) Biotype B (Hemiptera: Aleyrodidae).

The silverleaf whitefly Bemisia tabaci (Genn.) biotype B has become a serious problem for soybean cultivation because it can significantly reduce soybean productivity. The use of soybean cultivars resistant to whitefly attack is an important strategy in an integrated pest management (IPM) program. This study evaluated the preference for oviposition and colonization by B. tabaci biotype B on different soybean genotypes. In the free-choice test, the genotypes studied were 'IAC 17' and 'IAC 19' as the standards for resistance and 'IAC Holambra Stwart' as the standard for susceptibility, as well as BABR01-0492, BABR01-0173, BABR01-1259, BABR01-1576, BABR99-4021HC, BABR99-4021HP, 'Barreiras', 'Conquista', 'Corisco', 'BRS Gralha', PI274454, PI227687, and PI171451. In the no-choice test, the four best genotypes selected in the free-choice test, in addition to the susceptible and resistant standards were evaluated. Our data indicated 'Barreiras' as the most resistant genotype against B. tabaci biotype B. 'BRS Gralha', which was the least attractive to whitefly adults in the free-choice test, did not show resistance to insect attack when they were confined in cages in the no-choice test. Despite the high number of eggs observed, BABR01-1576 and BABR99-4021HC showed a reduced number of nymphs, indicating antibiosis. The genotypes with a high level of resistance can be used as a tool against B. tabaci in IPM or as a source of resistance in plant-breeding programs.

Seletividade de produtos fitossanitários utilizados na cultura da soja para pupas de Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) / Selectivity of pesticides used in soybean crops to Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) pupae

O objetivo do trabalho foi avaliar o efeito de produtos fitossanitários sobre pupas de Trichogramma pretiosum. Foram conduzidos três bioensaios em delineamento inteiramente casualizado com 11 tratamentos e cinco repetições. Em cada repetição, ovos de Anagasta kuehniella (Zeller, 1879) (Lepidoptera: Pyralidae) foram utilizados como hospedeiro alternativo, sendo aderidos em cartelas de cartolina de 1 cm2 com solução de goma arábica à 40% e oferecidos para o parasitismo por 24h. Após 168-192h do parasitismo, quando os parasitoides estavam na fase de pupa, as cartelas foram mergulhadas por cinco segundos nos tratamentos testados. Avaliou-se a sobrevivência dos indivíduos tratados e a redução na emergência dos parasitoides foi classificada segundo as normas da IOBC. Os inseticidas flufenoxurom (Cascade®) 10, diflubenzurom (Dimilin®) 20 e metoxifenozide (Intrepid 240SC®) 21,6 e 36 g i.a. ha-1 foram classificados como inócuos. Permetrina (Valon 384 CE®) 49,92; betaciflutrina 12,5 + imidacloprido 100 (Connect®) e gama-cialotrina (Stallion 150SC®) 3,75 g i.a. ha-1 foram levemente nocivos. Clorpirifós (Lorban 480BR®) 384 e espinosade (Tracer®) 24 g i.a. ha-1 foram moderadamente nocivos. Os herbicidas glifosato 720 + imazetapir 90 (Alteza®); s-metolacloro (Dual Gold®) 1920; flumioxazina (Flumyzin 500®) 60; clomazona (Gamit®) 1000; glifosato 2880 (Gliz 480SL®); dicloreto de paraquate 600 + diurom 300 (Gramocil®); glifosato 1200 (Roundup Ready®); foram classificados como inócuos e os herbicidas 2,4-D (DMA 806BR®) 1209; dicloreto de paraquate (Gramoxone®) 600; glifosato (Roundup Transorb®) 2592 g i.a. ha-1 classificados como levemente nocivos. Os fungicidas tiofanato-metílico (Cercobin 500 SC®) 400; flutriafol 60 + tiofanato-metílico 300 (Celeiro®); carbendazin (Derosal 500SC®) 250; tebuconazole (Folicur EC®) 150; flutriafol (Impact®) 125; tebuconazole 120 + trifloxistrobina 60 (Nativo®); epoxiconazole 30 + piraclostrobina 79,8 (Opera®); epoxiconazole (Opus SC®) 12,5; azoxistrobina (Priori®) 50; azoxistrobina 60 + ciproconazole 24 (Priori Xtra®) g i.a. ha-1 foram classificados como inócuos aT. pretiosumna fase de desenvolvimento avaliada (pupa). Dentre os produtos avaliados, aqueles classificados como inócuos devem ser priorizados no manejo integrado de pragas (MIP) por compatibilizar o uso do controle químico sem prejudicar o controle biológico. Do mesmo modo, os produtos classificados como moderadamente nocivos devem ser evitados sempre que possível ou substituídos por outro de menor impacto.

This study aimed to evaluate the effect of different pesticides onTrichogramma pretiosumpupae. Three tests were carried out with 11 treatments and 5 replications. Eggs ofAnagasta kuehniella (Zeller, 1879) (Lepidoptera: Pyralidae) were used as a factitious host affixed on 1cm2 pieces of cardboard using a non-noxious glue solution (40% gum arabic) and then offered to parasitism for 24 h. After 168­192 h from the parasitism, when the parasitoids were at the pupae stage, the pieces of cardboard were dipped for five seconds in the treatments. The parasitoid survival was evaluated and the emergence was classified accordingly to the IOBC guidelines. The insecticides flufenoxuron (Cascade®) 10, diflubenzuron (Dimilin®) 20 and methoxyfenozide (Intrepid 240SC®) 21.6 and 36 g a.i. ha-1 were classified as harmless. Permethrin (Valon 384CE®) 49.92, beta-cyfluthrin 12.5 + imidacloprid 100 (Connect®) and gammacyhalothrin (Stallion 150SC®) 3.75 g a.i. ha-1 were slightly harmful. Chlorpyriphos (Lorsban 480BR®) 384 and spinosad (Tracer®) 24 g a.i. ha-1 were moderately harmful. The herbicides glyphosate 720 + imazetapyr 90 (Alteza®), s-metolachlor (Dual Gold®) 1920, flumyoxazin (Flumyzin 500®) 60, clomazone (Gamite®) 1000, glyphosate (Gliz®) 2880, paraquat dichloride 600 + diuron 300 (Gramocil®), glyphosate 1200 (Roundup Ready®) were classified as harmless, and the herbicides 2.4-D (DMA®) 1209, paraquat dichloride (Gramoxone®) 600 and glyphosate (Roundup Transorb®) 2592 g a.i. ha-1 were classified as slightly harmful. The fungicides metil tiofanate (Cercobin 500SC®) 400, flutriafol 60 + metil tiofanate 300 (Celeiro®), carbendazin (Derosal 500SC®) 250, tebuconazol (Folicur EC®) 150, flutriafol (Impact®) 125, tebuconazol 120 + trifloxystrobin 60 (Nativo®), epoxiconazol 30 + piraclostrobin 79.8 (Opera®), epoxiconazol (Opus SC®) 12.5, azoxystrobin (Priori®) 50, azoxystrobin 60 + ciproconazol 24 (Priori Xtra®) g a.i. ha-1 were harmless toT. pretiosum pupae. Among the tested products, the harmless ones should be chosen in a program of integrated pest management (IPM) since it allows the use of pesticides without harm to the biological control. On the other hand, the moderately harmful pesticides should be avoided or replaced by another product with less impact whenever it is possible.

Efeito do tratamento de sementes com inseticidas no controle de pragas iniciais e na qualidade fisiológica das sementes em girassol / The effect of various insecticides on the control of initial pests and on the physiological quality of sunflower seeds

Avaliou-se o uso de inseticidas em tratamento de sementes de girassol no controle das pragas Cerotoma arcuatus (Olivier) (Coleoptera: Chrysomelidae), Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) e Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) e a influência desses inseticidas na qualidade fisiológica das sementes, durante o armazenamento. Os resultados obtidos mostraram que tiodicarbe 600 g i.a./ 100 kg de sementes proporcionou aproximadamente 80, 100 e 85% de controle de A. gemmatalis de 1º ínstar, S. frugiperda de 2º ínstar e adultos de C. arcuatus, respectivamente. Entretanto, esse mesmo tratamento foi ineficiente no controle de lagartas de S. frugiperda de 3º ínstar e de B. tabaci. No controle de adultos de C. arcuatus, além de tiodicarbe 600 g i.a./100 kg sementes que apresentou bons resultados, tiodicarbe + imidacloprido 157,5 + 52,5 g i.a., tiametoxam 210 e 280 g i.a., imidacloprido 245 e fipronil 50 g i.a./100 kg de sementes apresentaram eficiência acima de 80% no controle dessa praga. No controle da A. gemmatalis apenas fipronil 50 g i.a./100 kg sementes e azadiractina 10 e 20 g. i.a./100 kg de sementes proporcionaram valores menores que 80% de controle, nas doses testadas, enquanto que, para o manejo da mosca-branca, nenhum dos tratamentos estudados proporcionou controle superior a 80%. Nenhum dos inseticidas avaliados nos diferentes tempos de armazenamento (até quatro meses após o tratamento) prejudicou a germinação e a emergência das sementes.

The aim of this study was to test various insecticides in the treatment of sunflower seeds for the control of Cerotoma arcuatus (Olivier) (Coleoptera: Chrysomelidae), Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), and assessing their influence on the physiological quality of seeds during storage. The results showed that tiodicarb 600 g.a.i./100 kg of seeds achieved close to 80, 100 and 85% of control against first-instar A. gemmatalis, second instar S. frugiperda and adult C. arcuatus, respectively. However, this treatment was inefficient against third instar S. frugiperda and B. tabaci. Tiodicarb + imidacloprid 157.5 + 52.5; thiamethoxan 210; thiamethoxan 280; imidacloprid 245 and fipronil 50 g.a.i./100 kg of seeds also achieved 80% control against C. arcuatus adults. Against A. gemmatalis, only fipronil 50 g.a.i. and azarachtin 10 and 20 g.a.i./100 kg of seeds did not achieve more than 80% control. Against B. tabaci no tested treatment reached 80% of efficacy. None of the tested insecticides harmed seed germination or emergence during the different storage periods (up to 4 months after seed treatment).